Although a NSM event is a compelling r-process site for UFDs, given that r-process enhanced stars in UFDs might originate from a very rare and prolific event, rare SNe could be an alternative r-process site. Especially when considering r-process enhanced stars in the MW, there is an ongoing debate on their origin (e.g. , [1]}, ). For example,  have shown that NSMs alone may be insufficient to match observed Eu-abundances, in particular, the decreasing trend of \(\rm [Eu/Fe]-[Fe/H]\)  at \(\rm [Fe/H]>-1\)  in MW disk stars, suggesting a rare class of SNe as the origin of r-process elements.
